Backyard Aquaponics
A place to discuss aquaponics

Please explain [s]Jim[/s]..... ooops... sorry Milne....

[quote="veggie boy"]Yep - I gotta start raising more of my own seedlings outside of the AP bed. Once I get my greenhouse for the AP - I will have a dedicated shelf in it for doing this and will seup a hose off the pump for me to water the seed trays when I need to - make it really convenient and easy.

Seed is so cheap when you consider just how many there are in packets.[/quote
auto pot has an excelent seed raising setup which could be cobied using one smart valve see njds set up

VB- only when you get good germination rates. - and practice seed saving for next season.
It is said the harvest will be better the second season because the seed will naturalise(sp) any thoughts?
Ooops slight hijack
C1

I agree - my water level would also be contributing to loss of temperature at night. My tank was down to 19 degrees this morning. An indication of things to come - not good for the Jades.

diggers garden club claim all there seed can be re used over and over

C1 - I am a big seed saver, though some things just don't produce seed easily - or it just takes far too long. I don't think I have ever got seed from my spring onions or silverbeet for instance. I save seed from lettuce, toms, eggplants, spinach, pumpkins, melons, beans, peas and heaps more of my stuff. I tend to agree regarding your statement, if not only for the reason that I only ever grow the stuff a second time if it worked the first time.

Yep - diggers stuff is all traditional open pollinated stuff. Definitelly the way to go.

Sorry missed ths one in my nft pipes i put a 2 in riser onthe drain and when established take it out so while the plants establish the nft run full when growing water only runs along the botton

Ohh - forgot, most of my herbs and chillis are from my own seed stock also. Quite a few of my plants in my growbeds were self sown into the dirt garden then pulled out for the GB. Most of my lettuce in the GB and some toms and basil were self sown from previous GB grown plants. Eventually I suppost most of my plants will be grown from this method provided there are not season limitations.

yep there the ones.. stick with those F&F you can't go wrong!
Some crew just through them around and they selfsow,
poping up when the time is right for them.Good if you miss the MPh

Hmmm, yes water consumption is definately something requiring further documentation... But once again, there are so many contributing factors you really need to do it over at least a year... ATM I am using my hose to fill my large system. Every 4-5 days I stick the hose in and turn it on for 3-4 minutes.. Now all I need to do is measure how much that 3-4 minutes outputs... It's definately less water than what could support equivalent ground beds.

From a booklet outlining the aquaponics system at the CDC, Brooks, Alberta Canada:

Water use efficiency in Agriculture (Smith 2005)
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Agricultural Sector Liters of water per $100 output

Rice-------------------------------------------------------470,000
Cotton----------------------------------------------------160,000
Dairy-milk-----------------------------------------------147,000
Sugar-----------------------------------------------------123,900
Beef Cattle----------------------------------------------81,200
Vegetables---------------------------------------------37,900
Wheat and Grain-------------------------------------24,500
Hydroponic crops------------------------------------As low as 600

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(Note: I realize much of this is non related information and obviously is just averages, but I included it for the sake of completion)

Excerpt from booklet regarding their own water usage in a DFT raft system, fishtanks exposed to full sun in greenhouse(a quite coarse fish net covers the tanks but holes are not small enough to really be concidered as shade cloth):

"A negligible amount of water is removed from the system with solids in the system. For example, about 15 liters are removed every day from a system containing 71,000 liters, comprising about 0.02%. Water loss through evapo-transpiration will be the largest in aquaponics. However, it rarely exceeds 0.7% a day in greenhouse conditions in Alberta. Calculation show 497 liters of daily loss or 181.4 cubic m annually + 5.4 cubic m removed with solids. With average gross revenue of $47,440 ($11,040 from tilapia sales and $36,400 from basil sales) means a 394.3 liters per $100 of output, which is 65.7% more efficient than in the best hydroponics systems."

(Note: Acknowledge that there are many variables here. I posted this so people could see the information, not to try to prove anything)

I am privy to believe that aquaponics CAN be of the most water efficient methods of producing both protein and vegetables, depending on several conditions as has been noted here already.

How many people are covering their fish tanks? Drain pipes? Reducing exposed surface area could significantly reduce loss? but would that then prevent the water from being oxygenated properly?

I top up my system about every third day with about 30 ltrs . It varies a bit depending on how hot the days are. I notice it is starting to drop off now the days are getting shorter.
VB, my tank was down to 21 deg this morning. I have just covered the tank for the night for the first time this season.
Murray

Are you serious muzz? Only 10 litres per day? Surely just evaporation would be greater than that, let alon transpiration from plants. Let us know if you meant 300 litres every third day